A line has a slope of - 7 and includes the points (3, - 9) and (t, - 2). What is the value of t?
+9476 m = (y2 - y1)/(x2 - x1)
-7 = (-9 - (-2))/(3 - t)
-7 = (-7)/(3 - t)
-7(3 - t) = -7
3 - t = 1
- t = -2
t = 2
Here's a way to think of it. Slope is rise over run. The change in rise from the first point to the second is 7, so the change in run is going to be -1, because the slope is -7. So it is 3-1=2.
